Quantum tunneling is a fascinating quantum phenomenon where particles can pass through energy barriers that, according to classical physics, they do not have enough energy to overcome. Instead of needing enough energy to climb over a barrier, particles have a probability to “tunnel” right through it.
How It Happens:
- In quantum mechanics, particles are described by wavefunctions, which represent probabilities rather than definite paths.
- Even if a barrier is higher than the particle’s energy, the wavefunction extends slightly into and beyond the barrier, giving a non-zero chance that the particle appears on the other side.
- This effect has no classical equivalent and defies everyday intuition.
Where Quantum Tunneling Occurs:
- Nuclear fusion in stars, where particles tunnel through repulsive forces to fuse nuclei.
- Semiconductor devices like tunnel diodes and flash memory rely on tunneling for their operation.
- Scanning tunneling microscopes use tunneling electrons to image surfaces at the atomic level.
- Radioactive decay sometimes happens because particles tunnel out of the nucleus.
Why It Matters:
Quantum tunneling is essential for understanding many natural and technological processes that classical physics cannot explain. It highlights the probabilistic and non-intuitive nature of the quantum world, where particles can “cheat” classical barriers and open doors to new phenomena.